An aircraft of this type driven by muscular power is referred to in the French patent specification No. 883,293. Numerous other aircraft, usually intended for sporting purposes, have been developed for flight by manpower, with which in fact flights of up to several hundred meters have been achieved. The known aircraft are, however, extraordinarily unreliable. They are provided with disproportinately large wings, have poor manoeuvering properties and/or are relatively unserviceable for flying.